Automotive seat with a backrest whose position can be electrically adjusted

ABSTRACT

In the case of a vehicle seat ( 1 ), in particular rear seat or rear seat bench, having a seat part ( 2 ) and having a backrest ( 3 ) which has a foldover function brought about with an electric drive, the foldover function bringing about a folding over of the backrest ( 3 ) or of a backrest part ( 4, 5 ) relative to the seat part ( 2 ), an adjustment of the inclination and the folding over are to take place in a simple and convenient manner. This is achieved by the electric drive ( 6 ) having an inclination-adjusting function, it being possible for the adjusting speed of the electric drive ( 6 ) to be changed in such a manner that a different speed can be set in each case for the inclination-adjusting function and for the foldover function.

BACKGROUND OF THE INVENTION

The invention relates to a motor vehicle seat, in particular rear seator rear seat bench, having a seat part and having a backrest which has afoldover function brought about with an electric drive, the foldoverfunction bringing about a folding over of the backrest or of a backrestpart relative to the seat part.

The publication OE 197 37 269 C2 discloses a motor vehicle seat, inwhich the inclination of the backrest can be adjusted by an electricdrive in order to make different seat positions possible. This motorvehicle seat is provided with an electrically driven rotary adjustingfitting, one fitting part of which is connected fixedly to a seat-partframe and the other fitting part of which is connected fixedly to thebackrest frame, it being possible for the backrest frame to be set ininclination electrically about a horizontal inclination-adjusting axisand, in addition to this, being of mechanically or manually foldabledesign.

Another motor vehicle seat is shown and described in the publication OE199 16 709 C1. This motor vehicle seat, in particular rear seat or rearseat bench, is provided with a seat part and a backrest which can befolded onto the seat part which, with the backrest resting on it, can betransferred about a transverse axis arranged in its front region into anessentially upright position. This seat has automatic folding, in whichthe folding of the backrest and also the setting of the seat partupright and the transfer of the seat back into its operative positiontake place by means of cables driven by a motor-transmission unit. Inthis case, this seat can be operated both from the vehicle interior andfrom the trunk. However, this predominantly mechanical drive is complexin construction and limited in its adjusting function.

SUMMARY OF THE INVENTION

The invention is based on the object of providing a motor vehicle seatof the generic type, in which the adjustment of the inclination and thefolding over can take place in a simple and convenient manner.

This object is achieved by the electric drive having aninclination-adjusting function, it being possible for the adjustingspeed of the electric drive to be changed in such a manner that adifferent speed can be set in each case for the inclination-adjustingfunction and for the foldover function. Advantageous developments of theinvention are contained in the subclaims.

The invention makes it possible, without a complicated mechanicalconstruction, both to adjust the inclination of the backrest, in orderto set a comfortable seat position, and also to fold the backrest over,in order to increase the volume of the trunk. According to theinvention, different speeds can be set in each case, as a result ofwhich a first speed can be assigned to the adjustment of the inclinationand a second speed—deviating from the first speed—for the folding overof the backrest can be assigned to the electric drive.

Different adjusting speeds of the electric drive make it possible forthe inclination-adjusting function of the backrest to advantageously becarried out at a slower speed than that of the foldover function. Theslow speed has the advantage that the inclination of the backrest can beset precisely while the higher speed brings about a rapid implementationof the foldover function.

If each backrest-adjusting function, i.e. foldover andinclination-adjusting function, has a dedicated adjusting characteristicin each case, it is possible, for example, to carry out an adjustment inthe foldover function at low torque and an adjustment in theinclination-adjusting function at high torque. This firstly increasesthe safety because, for example given a low torque in the foldoverfunction, people cannot be injured by the small force of a pressing-downbackrest, and secondly the inclination of the backrest can be set athigher torque even when subjected to a load by a person. In this case,it is not necessary to assign a slow speed to the lower torque and ahigher speed to the higher torque. On the contrary, it is entirelyexpedient for the torque to be low given a higher speed in the foldoverfunction, and vice versa. In this case, the changing of the torque andof the rotational speed of the motor may also be undertaken by variousmotor windings.

In one advantageous development of the invention, provision is made forthe inclination of the backrest to be changeable in theinclination-adjusting function by the electric drive in a stepwisemanner. This makes it possible for a certain position to be set moreeasily and conveniently in comparison to an infinitely variableadjustment—in particular with a stepping motor.

It is cost-effective if the electric drive has an electric motor whichis common to both adjusting functions, it being possible, in principle,for there to be two motors, for example a first, relatively powerfulstepping motor for the inclination-adjusting function and a second,smaller d.c. motor for the foldover function.

By means of an electronic or mechanical torque limitation in thefoldover function, which is provided in a further advantageousrefinement of the invention, in which, when an impermissible, definedvalue is exceeded, in the simplest case the electric drive is switchedoff as a consequence of measuring the motor current, people or objectsare reliably protected in a simple manner from folding-over backrests.This torque limitation has proven particularly favorable if shoppingbags with certain foodstuffs or other sensitive objects have been lefton the rear seat and cannot be seen when the foldover function isoperated from the trunk.

If the vehicle seat is provided with one or more seat occupationsensors, the safety can be additionally increased. In this embodiment, aperson sitting on the rear seat is detected and the foldover function isimmediately switched off automatically. It is particularly advantageousin particular if the seat occupation sensor is functionally connected tothe electric drive via a control unit in such a manner that, when theseat is occupied, the foldover function is blocked and theinclination-adjusting function is not blocked. This can expediently beachieved by means of a changeover switch.

In one preferred embodiment, provision is made, in the foldoverfunction, for the electric drive to be actuable from the passengercompartment—preferably from the particular seat—by a first operatingswitch, and separately from the trunk by a second operating switch, and,in the inclination-adjusting function, for it to be actuable from theparticular seat. Folding over is then conveniently possible, even if thevehicle is parked between pillars in a basement garage, since theoperation from the trunk can easily take place.

Convenient activation of the foldover function is possible from everyposition and also outside the vehicle if, according to a furtheradvantageous refinement of the invention, provision is made for awireless remote control which can be designed in a known manner as aradio or infrared control system. Activation may also take place bymeans of a speech recognition module.

It is also favorable if the electric drive is a combination of a motorand transmission. A combination of a motor and transmission—inparticular in a compact construction—enables the torque to be suitablyincreased according to requirements or enables the speed of therotational speed of the motor to be matched to the required drivingspeed.

It is also advantageous if the electric motor of the electric drive hastwo speeds—by changing the motor power.

The invention is explained in greater detail with reference to anexemplary embodiment in which further advantages of the invention andfurther features are described in greater detail.

BRIEF DESCRIPTION OF THE DRAWINGS

The single FIGURE of the drawing shows a perspective illustration of avehicle seat.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The FIGURE shows a vehicle seat 1 which is designed as a rear seat benchhaving a seat part 2 which is common to a plurality of backrest parts.The rear seat bench has a two-part backrest 3 on which has a firstbackrest part 4 and a second, smaller backrest part 5. In order tochange the position of the second backrest part 5, an electric drive 6is arranged in the vicinity of the axis of rotation 7 of the backrest 3and on the backrest part 5, this drive being positioned in the vicinityof one end 8—preferably the outermost end in each case with respect tothe backrest part—of the axis of rotation 7. The electric drive 6comprises a motor 9 and a transmission 10, the transmission 10 beingmechanically connected directly to the axis of rotation 7. The axis ofrotation of the motor is situated in a space-saving mannerperpendicularly with respect to the axis of rotation 7, it beingpossible for the motor to be controlled at two speeds.

Actuating switches 11 and 12 are provided to electrically actuate thebackrest or one or more backrest parts 4, 5.

In the exemplary embodiment shown, although only one electric drive 6for the backrest part 5 is shown, the other backrest part 4 is alsoprovided analogously to this with a further electric drive according tothe invention (not shown).

According to the invention, the electric drive 6 has two differentadjusting speeds, it being possible for the adjusting speed of theelectric drive 6 to be changed in such a manner that a different speedcan be set in each case for an inclination-adjusting function and for afoldover function, so that both an electric adjustment of theinclination of the backrest 3 is possible, in order to set a comfortableseat position, and an electric folding over is possible, in order toincrease the volume of the trunk, the trunk 16 having been enlarged, asillustrated in the FIGURE, by the backrest part 5 being folded over.

According to the invention, different speeds can therefore be set ineach case, as a result of which the electric drive 6 can be assigned afirst speed for the adjustment of the inclination and a secondspeed—deviating from the first speed—for the folding over of thebackrest.

The motor 9 therefore has two speeds, a first, slow speed for adjustingthe inclination of the backrest, and a second, rapid speed for foldingover the backrest 3 or one or more of the backrest parts 4 and/or 5. Inaddition, the electric drive 6 can be provided with two adjustingcharacteristics, a first at high torque, for adjusting the inclinationof the backrest, and a second, at low torque, for folding over thebackrest.

The electric drive 6 implemented with the combination of the motor andtransmission, comprising the motor 9 and the transmission 10, can beoperated at two different adjusting speeds. In the inclination-adjustingfunction of the backrest 3 or, assumed here, of the backrest part 4,starting from a position inclined to the rear, at maximum an essentiallyvertical backrest position can be reached.

Starting from the position shown in the FIGURE, a rearward inclinationof the backrest part 4 takes place only at a relatively slow speed inorder to achieve a setting of the backrest in a manner which is aspleasant as possible. It is also readily possible for a rough setting ata somewhat more rapid speed than in a fine setting to be provided in theinclination-adjusting function. The somewhat higher speed can be set bypressing an operating switch or an operating button for a longer period,as is customary when “winding on” in CD players or when adjusting thetime in digital clocks. The slow speed has the advantage of enabling theinclination of the backrest to be set precisely.

The inclination-adjusting function has an adjusting characteristic withhigh torque. The inclination of the backrest 3 can be set more gentlyand precisely at higher torque than at low torque. It is entirelyexpedient for the torque to be relatively high given a low speed in thisfunction. It is then possible for a seat position which is inclinedgreatly to the rear to be pushed or moved forward into an uprightposition virtually without any effort. The torque can also be changed byswitching on a further motor winding or by changing the magneticproperties of the motor 9.

An inclination of the backrest 3 in the inclination-adjusting functioncan be changed by the electric drive 6 in an infinitely variable manneror, in particular, in a stepwise manner, the motor 9 in the latter casebeing a stepping motor.

A higher adjusting speed—at least higher in comparison to one of aplurality of speeds for the backrest 3 (see above “winding on” in CDplayers)—can be achieved in the foldover function, the higher speedbringing about a desired, rapid implementation of the folding-overprocess. The foldover function is not restricted just to the tippingforward, but also comprises an automatic return of the seat back intoits operative position, which corresponds to the position of thebackrest part 4 in the FIGURE.

In comparison to the inclination-adjusting function, in the foldoverfunction, in principle, only a relatively low torque is required, but isalso advantageous for safety reasons. At a low torque in the foldoverfunction, people, in particular children, cannot be injured by the lowforce of a pressing-down backrest. However, the movement of the backrest3 in the foldover function has a higher speed—in contrast to that in theinclination-adjusting function—so that the trunk is enlarged as rapidlyas possible.

An electronic torque limitation in the foldover function makes itpossible, when an impermissible, defined value is exceeded, for themotor 9 to be switched off, the motor current being measured and asignal when there is an impermissible current being passed on to acontrol unit 14. However, a motor safety switch or the like may also beprovided for this. Small children are thereby also protected, withoutadditional sensors, in a simple manner from folding-over backrests. Inorder to additionally increase the safety, in the exemplary embodimentillustrated a plurality of seat occupation sensors are provided, onlyone seat occupation sensor 13 of which is illustrated. In the exemplaryembodiment shown, a further seat occupation sensor is arranged in theregion of the smaller backrest 5 and is also, like the seat occupationsensor 13 which is shown, integrated in the seat part 2. It is alsoreadily possible for two seat occupation sensors to be arranged in theseat part 2 in the region of the larger backrest 3, so that there are inall three uniformly distributed seat occupation sensors, correspondingto the maximum number of people for whom a rear seat is usuallyprovided.

In the exemplary embodiment shown, the safety is increased by acombination of torque limitation and seat occupation sensors 13, aperson or more than one person sitting on the rear seat or rear seatbench being detected by one or more seat occupation sensors 13, and arear switch 12 immediately being blocked and a front switch 11 beingchanged over to inclination function.

The seat occupation sensor 13 and all of the seat occupation sensorswhich are not shown are functionally connected to the electric drive 6via the control unit 14, the control unit 14 being designed in such amanner that, when a seat is occupied, the foldover function is blockedand the inclination-adjusting function is not blocked. The control unit14 is connected electrically to the operating switches 11, 12 via lines,but also to the seat occupation sensors 13 via a control line 15. Theoperating switches 11, 12 are described in greater detail further on.The lines may also be replaced by a bus line and do not have to beindividual lines as shown in the FIGURE.

In the exemplary embodiment, the electric drive 6 for the two adjustingfunctions has a common electric motor 9. In principle, there can be twomotors, for example a first, relatively powerful stepping motor for theinclination-adjusting function and a second, smaller d.c. motor for thefoldover function.

In this case, the electric motor 9 of the electric drive 10 has twospeeds by changing the voltage of the motor, one speed being providedfor the folding over and the other for the inclination.

In the exemplary embodiment shown, the electric drive 6 is a combinationof a motor and transmission, the transmission 10 (cf. ref. no. 8) beingarranged in the vicinity of the electric motor 9 and not having anycables and cable drums or other structurally complicated means. Thecombination of a motor and transmission in this compact constructionenables the torque to be adapted in a suitable and simple manner to theweight or the adjusting force of the backrest part 4 or 5 or to thespeed of the motor 9 or to the desired driving speed.

The motor shaft of the electric motor 9 drives a toothed-wheeltransmission which moves the backrest 3 or a backrest part 4 or 5 at areduced rotational speed in comparison to the rotational speed of themotor shaft.

The transmission 10 is furthermore designed as a deflecting transmissionwith a 90° deflecting angle, as can be seen by the vertical arrangementof the motor with respect to the axis 7.

Although the exemplary embodiment is concerned with a rear seat, it canbe transferred just as well to a front seat in order to make possible anarrow, but long trunk, in which, for example, long shelves packed in anarrow manner can be transported on the rear surface of the folded-overfront passenger seat, on the rear surface of the folded-over backrestpart and in the actual trunk 16 itself. The driver's seat may also beequipped with these functions in order to be able to provide a largebed, in which case all of the rear seat backs and front seat backs arethen folded over. In addition to the functions with regard to thebackrest, in particular the foldover function, one or more seats may beelectrically displaceable and/or comprise other electric functions inorder to be able to provide, for example, a sleeping surface which is aseven and gap-free as possible.

The electric adjustment conveniently permits, as already indicated,considerable variation options for the vehicle interior and trunk, whichsatisfies the trend for versatile use of a vehicle. In particular, tabletop or workplace functions which are programmed in an electric controlsystem can be realized, in which case, as already customary, the rearside of the backrest can be used as a table surface or else transportingor sleeping functions can be realized.

For the foldover function of the backrest parts 4 and 5 shown in theFIGURE, in the very simplest case there can be a switch or a changeoverswitch or both, and these can be used to fold over only the smallerbackrest part 5 or only the larger backrest part 4 or both backrestparts 4 and 5 simultaneously. However, operation may also take placefrom the dashboard, in particular by means of a menu-driven touch panelor else by a menu-driven, wireless remote controls.

In principle, the electric folding over is not restricted only tofolding forward, but may also comprise an electric folding rearward,which is expedient in the case of a sleeping position.

In the exemplary embodiment shown, however, only a forward folding isprovided, with, in the foldover function, the electric drive 6 beingactuable from the seat by a first operating switch 11 or from the trunk16 by a second operating switch 12. In the inclination-adjustingfunction, only an operation from the seat, in particular from the frontseat region, is possible.

In this exemplary embodiment, there are therefore a total of threeoperating switches for operating the rear parts 4 and 5, namely a firstoperating switch 11, which is arranged on the right-hand side in theseat part 2 and serves to adjust the inclination of the seat or for thefolding over of the smaller backrest part 5, a second operating switch12, which is arranged in the trunk 16 and is provided for folding overone or more backrest parts 4 and/or 5, and a third operating switch (notshown) on the left-hand side of the seat for analogously adjusting orfolding over the larger backrest part 4.

The operating switches 11, 12 also have two directional functions ineach case, i.e. folding forward or sitting upright or inclining forwardor inclining rearward, the directional function not being required inthe case of the foldover function if there are end position sensorswhich are connected to the control unit 14, so that, by simple pressingof one of the operating switches 11 or 12 the backrest parts 4 and/or 5,the direction of rotation of the electric motor 6 can be automaticallydetermined and set.

A folding-over process when operated from the trunk is particularlyconvenient if the vehicle is parked between pillars in a basement garageor if one simply happens to be by the trunk.

A wireless remote control (not illustrated) which can be designed in aknown manner as a radio or infrared control system enables the rear seatparts 4 and/or 5 to be folded over in an analogous manner from everypoint and also from outside the vehicle.

The vehicle seat according to the invention can be a rear seat benchwith a ratio of spacing of the backrest parts of 40%-60%, 50%-50%, 100%and other values. In the exemplary embodiment shown, the backrest part 5has, as can be seen, approximately 40% of the entire width of thebackrest 3, and the backrest part 4 therefore has approximately 60%.

In this exemplary embodiment, although there is a common electric motor,there may be, in principle, as already explained, two motors, one, forexample, for the inclination-adjusting function and a further one forthe foldover function.

In addition, in the inclination-adjusting function various angles ofinclination can be set in an infinitely variable manner, by contrast, inthe exemplary embodiment shown, only two end positions are possible inthe foldover function, namely a folded over backrest position (seebackrest 5) and a backrest position suitable for sitting (see backrest4), i.e. essentially upright backrest position or operative position.The unfolded end position in the operative position can either always bean essentially upright backrest position, so that the backrest alwayshas the same starting position after a folding-over process, or it mayalso be a previously set position inclined more severely to the rear, sothat an individually set inclination is retained after a folding-overprocess and does not have to be re-set. The same can be realized bymeans of the control unit 14.

The invention is not confined to the exemplary embodiments illustratedand described, but encompasses all of the variants of equivalent effectwithin the meaning of the invention. Furthermore, the invention is alsonot yet confined to the combination of features defined in claim 1 butcan also be defined by any other desired combination of particularfeatures of all disclosed individual features. This means that, inprinciple, virtually any individual feature of claim 1 can be omitted orreplaced by at least one individual feature disclosed elsewhere in theapplication. To this extent, claim 1 is to be understood merely as afirst attempt at formulating the invention.

1-12. (canceled)
 13. A vehicle seat comprising: a seat part; a backrestand an electric drive coupled to the seat part and backrest, wherein thebackrest is moved relative to the seat part in one of a fold-overfunction and an inclination-adjusting function by adjusting the speed ofthe electric drive in such a manner that a different speed can be set ineach case for the inclination-adjusting function and for the fold-overfunction.
 14. The motor vehicle seat as claimed in claim 13 wherein thedrive (6) has two adjusting speeds, a higher speed being provided forthe foldover function and a lower speed being provided for that of theinclination-adjusting function.
 15. The motor vehicle seat as claimed inclaim 13 wherein the foldover function and the inclination-adjustingfunction each have a dedicated adjusting characteristic.
 16. The motorvehicle seat as claimed in claim 13 wherein the inclination of thebackrest (3) can be changed in the inclination-adjusting function by theelectric drive (6) in a stepwise manner—in particular with a steppingmotor.
 17. The motor vehicle seat as claimed in claim 13 wherein theelectric drive (6) has an electric motor (9) which is common to all ofthe adjusting functions.
 18. The motor vehicle seat as claimed in claim13 wherein the electric drive (6) has an electronic or mechanical torquelimitation.
 19. The motor vehicle seat as claimed in claim 13 whereinthe seat part (2) has at least one seat occupation sensor (13).
 20. Themotor vehicle seat as claimed in claim 19, wherein the seat occupationsensor (13) is functionally connected to the electric drive (6) in sucha manner that, when the seat is occupied, the foldover function isblocked while the inclination-adjusting function is not blocked.
 21. Themotor vehicle seat as claimed in claim 13 wherein, in the foldoverfunction, the electric drive (6) can be actuated from the passengercompartment—preferably from the seat and/or from the dashboard—by afirst operating switch (11), and can be actuated from the trunk by asecond operating switch (12) and, in the inclination-adjusting function,can be actuated from the seat—in particular from the front seat region.22. The motor vehicle seat as claimed in claim 13 wherein the backrest(3) or one or more backrest parts (4, 5) can be folded over by wirelessremote control.
 23. The motor vehicle seat as claimed in claim 13wherein the electric drive (6) is a combination of a motor andtransmission.
 24. The motor vehicle seat as claimed in claim 13 whereinthe electric drive (6) is positioned in the vicinity of one end (8) ofan axis of rotation (7) and is integrated in the backrest (3) or atleast a backrest part (4, 5).